JPH01282903A - Antenna system - Google Patents

Abstract

PURPOSE:To attain the transmission reception of a radio wave over a wide frequency range by making a stub by a substance whose conductivity is varied depending on the intensity of irradiation light and varying the intensity of the irradiation light so as to apply impedance matching. CONSTITUTION:The stubs 7, 8 are made of a substance whose conductivity is varied by the intensity of light. When the stubs 7, 8 are not irradiated with the light, a reflected voltage ratio is minimized at a frequency f0, the reflected voltage ratio is minimum at a frequency f1, when the stubs 7, 8 are irradiated with the light, and the impedance is matched. In the case when the frequency band to be used is f0-f1, the stubs 7, 8 are irradiated by an optical signal lighted by diodes 9, 10 via optical fibers 11, 12 at a frequency close to the frequency f1 to make the diodes nonconductive thereby disconnecting the stubs from the dipoles 2a, 2b. Thus, the antenna is matched at the frequency f1. On the other hand, if the frequency is close to the frequency f0, the diodes 9, 10 are not lighted, the conductivity is increased and the antenna is matched at the frequency f0.

Description

[Detailed description of the invention] [Industrial application field] This invention is for impedance matching.

This invention relates to an antenna device in which a metal whose conductivity changes depending on the intensity of light is connected to the antenna.

[, Conventional technology]

FIG. 4 is a diagram showing the configuration of a conventional antenna device disclosed in, for example, Jikai Publication No. 60-282894.

In the figure, C11 is a dielectric plate, and (2a) and (2b) are dipoles.

(5a) and (5b) are parallel 28. +51. (61 is a capacitive stub with an open end having a micro-strive line configuration.

In this antenna device, dipoles (2a), (2b)
A stub +51 is placed near the connection of the two parallel wires (3a) and (3b). (61 are connected in parallel. This stub i51. (6) allows the desired voltage standing wave ratio in the desired frequency band. Since the conventional antenna device is configured as described above, impedance matching at a specific frequency is possible. However, as the radio wave environment has become more severe in recent years, it has become necessary to transmit and receive radio waves in a wide frequency band with a single antenna.In the above cases, conventional antenna devices cannot However, there was a problem in that the frequencies at which impedance matching could be achieved were limited.

This invention was made to solve the above-mentioned problems, and aims to obtain an antenna device with impedance matching over a wide band. The stub metal is made of a material whose rate changes, and the strength of the light irradiating the stub is changed depending on the frequency used, thereby changing the conductivity of the stub, making it possible to transmit and receive radio waves over a wide frequency range.
Effect] The antenna device according to the present invention includes a stub made of a material whose conductivity changes depending on the intensity of the irradiated light, and performs impedance matching by changing the intensity of the irradiated light, thereby transmitting and receiving radio waves in a wide frequency range. enable.

[Embodiments of the invention]

FIG. 1 is a diagram showing an embodiment of the present invention. In the first factor, (7) and (8) are NFC stubs made of a material whose conductivity changes depending on the strength of light, (91, αa is a laser diode, αυ, α2 are optical fibers.

The present invention will be explained in detail below. Figure 2 shows the frequency characteristics of the reflected voltage ratio at the antenna terminal when the stubs (71, (8)) are not irradiated with light in the antenna device shown in Figure 1. The reflected voltage ratio is minimum at fQ.

In other words, impedance matching is achieved. Next, FIG. 3 shows the frequency characteristics of the reflected voltage ratio when the stubs (7) and (8) are irradiated with light in the antenna device of the first cause. In this case, the antenna device has a minimum reflected voltage ratio at frequency f1, that is, impedance matching is achieved.

If the frequency band used is fo-fl, at frequencies close to fl, the laser diode (
9), α1y&: emit light, and the laser diode (9
The optical signal generated at 1, (1G) is transmitted by optical fiber cable an, az, and the stub (71, (8
). When the stubs (71, (81) are irradiated with an optical signal, their conductivity becomes zero and they become non-conductive, and the stubs (71, +81 are dibo/l/ (2a) + (2
b) Separated from A.

Therefore, the antenna characteristics are matched at the frequency f1. When the operating frequency is close to fO, the laser diode +91. aGf
Without emitting light, the conductivity of the stub is increased and matching is achieved at two frequencies fo.

〔Effect of the invention〕

As described above, according to the present invention, since the conductivity of the stub is controlled by an optical signal, transmission and reception of a wide frequency band is possible with one antenna.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of an antenna device according to an embodiment of the present invention, Fig. 2 is a diagram showing the frequency characteristics of the reflected voltage ratio when the stubs are all connected, and Fig. 3 is a diagram showing the frequency characteristics of the reflected voltage ratio when the stubs are disconnected. FIG. 4 is a diagram showing the frequency characteristics of the reflected voltage ratio, and is a diagram showing a conventional antenna device. In the figure, (1) is a galvanic plate v (2a) and (2b) is a dipole. (5a), (3'b) are two parallel lines, 15+, (6
1 is a metal stub. (71, (8) is a stub made of a material whose conductivity changes depending on the intensity of the irradiated light, (91, αc1 is a laser diode, all, R1214 optical fiber. The same reference numerals in Figure 1 are Indicates the same or equivalent part.

Claims (1)

[Claims] In an antenna device that transmits or receives radio waves by feeding power to a linear or plate-shaped metal piece, the antenna is made of a material whose conductivity changes depending on the intensity of the irradiated optical signal and is electrically bonded to the metal piece. A stub, a laser diode, and an optical fiber are provided for impedance matching, and an optical signal generated by the laser diode is irradiated to the stub through the optical fiber to control the degree of electrical coupling between the stub and the metal piece. An antenna device that is characterized by being able to efficiently transmit or receive radio waves over a wide frequency band.